Distances between two water supply entries into a building. Installation of water supply inlets into buildings. Water supply inlets, water metering units and devices for measuring the amount of water consumed
On the general plan of the site we outline the entrance, i.e. section of the water pipeline from the point of connection into the city network to the water metering station, taking into account the following requirements:
a) the shortest length;
b) a right angle to the wall of the building;
c) central location in relation to the building;
d) proximity to the location of the water metering unit.
A well is installed at the point where the inlet is connected to the city water supply pipe. To empty the inlet, it is laid with a slope of 0.002 to the side of the well.
The water supply inlet is located 0.4 m above the drainage pipes, the distance in plan between them must be at least 1.5 m with an inlet diameter of up to 200 mm. If the inlet intersects with the drainage line and the vertical distance is less than 0.4 m, the inlet is laid in a steel casing, the length of which is 5 m on both sides of the intersection point.
The depth of the input H in, m, is determined by the formula
N in = N in + 0.5,
where N pr is the specified freezing depth, m.
The intersection of the inlet with the walls of the basement should be carried out in dry soils with a gap of 0.2 m between the water supply and building structures by sealing the hole in the wall with waterproof and gas-proof elastic materials, in wet soils - with the installation of oil seals.
The input diameter is determined during the hydraulic calculation of the network.
Water consumption is measured using cold water meters installed at the entrances to the building.
A water metering unit, consisting of a water meter, shut-off valves, a drain valve and a bypass line with a valve on it, is installed at a distance of at least 0.5 m from the inner wall of a room with lighting and a temperature of at least 5°C. A bypass line should be provided if:
There is one water supply entry into the building;
The water meter is not designed to handle fire water flow.
5.1.2 Internal water supply network
When designing, you should strive for the shortest length of pipelines. In the drawings, all plumbing fixtures, fittings and pipelines must be shown with symbols in accordance with Appendix A. On the floor plan (Appendix, B), depending on the chosen type of installation of risers (Fig. 1.2), we outline the installation locations of water risers and mark them: StV 1 -1, StV 1 - 2, etc.; We show the connections to sanitary fixtures.
a) sewer riser D=50 mm and water riser;
b) sewer riser D=100 mm and water riser;
c) sewer riser D = 100 mm and two water risers.
Figure 1 – Mounting positions of risers with open installation
a) corner water pipe riser;
b) corner water supply riser and sewer riser;
c) hot and cold water supply risers with a corner sewer riser.
Figure 2 – Mounting positions of risers for hidden installation
We transfer the locations of the risers to the basement plan, design the main pipeline and connect it to the input.
The main pipelines connect the bases of the risers with the water metering unit; they are laid along the internal walls of the basement at a distance of 0.2 to 0.4 m from the ceiling.
On the outside of the building, for every 20 - 70 m of the perimeter, one watering tap should be provided, which is shown on the basement plan (Appendix B) and axonometric diagram (Appendix D).
We lay horizontal pipelines with a slope of at least 0.002 towards the inputs or risers. The connections from the risers to the water fittings are made 0.10 - 0.25 m above the floor. To disconnect sections of the water supply system, we install shut-off valves (the nominal diameter of the pipes is no more than 50 mm) or gate valves. They are required on branches from main pipelines, at the bases of risers, at entrances to apartments, in front of float valves of flush barrels and watering taps. The entire water supply network is designed from plastic pipes and fittings made of polyethylene, polypropylene and other plastic materials. It is also allowed to use copper, bronze, brass and steel pipes with internal and external coatings against corrosion.
We draw a diagram of the designed water supply network in an axonometric projection (isometry appendix D) and use it to carry out hydraulic calculations and draw up a specification of materials. If all floors have the same water distribution devices, then it is enough to show them only for the top floor; on the remaining floors we show the branch from the risers. The thickness of the floors is assumed to be 0.2 - 0.3 m.
5.1.3 Determination of estimated water flow rates in water supply systems and hydraulic calculations
Cold water supply and drainage systems must provide water supply and wastewater disposal, which in turn must correspond to the estimated number of water consumers or the number of installed sanitary fixtures.
The maximum second water flow rate in the calculated network section q, l/s, is determined by the formula
,
where q 0 – water consumption by the device, l/s; α is the coefficient determined in accordance with the recommendations of the standards or Appendix 3 of these instructions.
The second water consumption q0 of a water tap (device), assigned to one device, should be determined for different devices serving the same consumers in the dead-end network section, in accordance with Appendix 3 of the standards or Appendix K of these instructions.
The probability of operation of sanitary fixtures in sections of the water supply network with the same consumers in the building without taking into account changes in the U/N ratio is determined by the formula
,
where is the rate of cold water consumption at the hour of greatest consumption, l/h; U – number of water consumers; N – number of sanitary fixtures.
Hydraulic calculations of a dead-end water supply network are performed in the following sequence. The axonometric diagram of the water supply system (Appendix E) is divided into design sections - parts of the network with a constant flow rate and pipe diameter (usually between two water distribution points), and their lengths are determined. The first calculation section starts from the dictation device, which is furthest from the input. When choosing a dictating water tap, you should take into account the value of its operating pressure (free pressure Hf m.water.st.), adopted in accordance with regulatory requirements or Appendix K of these instructions.
The calculation result can be conveniently presented in a table
Table 5.1 Parameters for hydraulic calculation of water supply
Example of table calculation for this option (see Appendix B)
| 1-2 | 0,00708 | 0,014 | 0,2 | 0,2 | 0,2 | 1,17 | 1,52 | 538,79 | 700,42 | |||
| 2-3 | 0,00708 | 0,021 | 0,217 | 0,2 | 0,217 | 1,17 | 0,55 | 193,64 | 251,73 | |||
| 3-4 | 0,00708 | 0,028 | 0,233 | 0,2 | 0,233 | 1,32 | 3,44 | 1556,96 | 2024,05 |
| 11-12 | 0,00708 | 0,510 | 0,685 | 0,2 | 0,685 | 1,32 | 0,48 | 103,36 | 134,37 | |||
| 12-13 | 0,00708 | 0,644 | 0,773 | 0,2 | 0,773 | 1,452 | 0,44 | 104,08 | 135,30 | |||
| 13-14 | 0,00708 | 1,034 | 0,982 | 0,2 | 0,982 | 1,03 | 3,74 | 321,55 | 418,02 | |||
| ΣH = | 9533,23 | |||||||||||
| input | 0,00708 | 1,034 | 0,982 | 0,2 | 0,982 | 1,03 | 3,74 | 7333,26 | 418,02 |
Calculation example:
We select the most distant dictating device - a bathtub with a washbasin - and designate area 1-2 (see Appendix E). There are two appliances in this area (bathtub and washbasin).
The probability of simultaneous operation of devices is determined by the formula
,
where is the consumer’s rate of cold water consumption at the hour of greatest water consumption, l/h;
Cold water consumption by sanitary fixtures, l/s.
The value is determined by the difference between the general rate of water consumption and hot water consumption, l/h (add. K):
We take the second flow rate of cold water (adj. K) equal to 0.2 l/s (for a bathtub as for a device with the highest flow rate). Then
,
Based on the value N∙P = 2∙0.00708 = 0.014 for section 1-2, we determine the coefficient α = 0.2 (according to Appendix I). Estimated flow rate, l/s, in the first section
Similarly, we determine the estimated costs for other sections of the network.
Based on the calculated water consumption (Appendix L) for the most economical speeds in each section, we find the diameters of the pipes and the amount of hydraulic pressure loss - 1000 i.
The speed of water movement in pipelines of internal water supply networks should not exceed 3 m/s (optimally 0.9-1.3 m/s), and pressure loss (1000 i) should be minimal.
For section 1-2: water flow q=0.2 l/s
We select a pipe d = 15 mm, V = 1.17 m/s (this is more than 0.9 and less than 1.3 m/s) and from here 1000 i= 354. The length of the section is looked at on the floor plan and the axonometric projection of the water supply system. The nominal diameter of the water meter (water meter) should be selected based on the average hourly water consumption for the period of consumption (day, shift), which should not exceed the operational one, accepted according to Table 5.2.
The type of meter we accept is turbine or vane. The meter only measures the volume of water that has passed in a certain amount of time.
A meter with an accepted nominal diameter must be checked for missing the maximum (calculated) second water flow for domestic and drinking needs, at which the pressure loss in vane meters should not exceed 5 m, in turbine meters - 2.5 m.
Table 5.2 Data from UVK type high-speed water meters
| Diameter of nominal diameter of the meter, mm | Options | ||||||
| Water consumption, m 3 / h | Sensitivity threshold, m 3 / h, no more | Maximum volume of water per day, m3 | Hydraulic resistance of the meter, S, m/(l-s -1) 2 | ||||
| minimum | operational | maximum | |||||
| Winged | |||||||
| 0,03 | 1,2 | 0,015 | 14,5 | ||||
| 0,05 | 2,0 | 0,025 | 5,18 | ||||
| 0,07 | 2,8 | 0,035 | 2,64 | ||||
| 0,10 | 4,0 | 0,05 | 1,3 | ||||
| 0,16 | 6,4 | 0,08 | 0,5 | ||||
| Turbine | |||||||
| 0,30 | 12,0 | 0,15 | 0,143 | ||||
| 1,50 | 17,0 | 0,6 | 0,0081 | ||||
| 2,0 | 36,0 | 0,7 | 0,00264 | ||||
| 3,0 | 65,0 | 1,2 | 0,000766 | ||||
A bypass line for cold water meters is required if there is one input and it is calculated to allow the maximum
We find the pressure loss along the length as the product of the value 1000i of the hydraulic slope and the length of the section L.
Pressure loss in sections of cold water supply systems N, m water column, is determined by the formula
,
where is the pressure loss along the length, m; k l= 0.3 (for drinking water supply networks of residential buildings).
Necessary (required) pressure N TR, m water. st, at the point where the input is connected to the city network, ensuring normal water supply to the dictating device, is determined by the formula
,
where is the geometric height of the water supply from the point where the inlet is connected to the city water supply pipe to the mark of the dictating device m;
– free pressure at the dictating device, m of water. Art.;
– total pressure loss in the building, m of water. Art.
The total pressure loss in the building is determined by the formula
The pipeline from the external water supply network to the internal water supply network (to the water metering unit or shut-off valves located inside the building) is called the input.
The inlet usually consists of the following elements: a device for connecting to an external water supply network or a yard water supply network of a pipeline from the point of connection to the water metering unit or shut-off valves, including sealing the passage of the pipeline into the building.
The inlet can be connected to the external water supply network in one of the following ways:
1) to tees, crosses or plugged holes left during the construction of the city water supply network;
2) inserting a tee or directly connecting a pipe by welding;
3) using a saddle.
The saddle is a cast-iron shaped part that is attached to the pipe with a clamp on a rubber gasket for connecting shut-off valves (through tap or gate valve). According to the design of the saddles there are threaded, flanged and bell-shaped (Fig. 14, a - V). To drill a hole in the pipe, a drilling device is attached to the shut-off valve (Fig. 15).
At the point where the input is connected to the external water supply network, a well with a diameter of at least 700 mm is installed, in which shut-off valves (valve or gate valve) are placed to disconnect the input during repairs.
For the installation of inputs, cast iron socketed water pipes with a diameter of 50 mm or more, steel pipes with anti-corrosion bitumen insulation and, in some cases, plastic pipes are used.
After drilling the hole, the shaft with the drill is raised, the valve is closed, and the pressure in the upper chamber is released. The head with the upper chamber is removed and the valve (plug) is welded.
The inlets (if there are two of them) are connected to different sections of the external water supply network or to one main line, but with a separating valve installed on it.
Rice. 14. Connecting the input using a saddle:
A - threaded saddle; b–flange saddle; V – bell-shaped saddle.
Rice. 15. Hole drilling installation:
1 – pipe; 2 – clamp; 3 – saddle; 4 – plug valve; 5 – drilling device; 6 – nut with seal sleeve; 7 – ratchet; 8 – drill.
The depth of the inlet pipes depends on the depth of the external water supply network, which is determined taking into account the depth of soil freezing. The minimum depth for laying input pipes (in the absence of soil freezing) is 1 m. The input is laid with a slope of 0.005 towards the external network to allow it to be emptied.
The shortest horizontal distance from the input pipes to other underground utilities is as follows:
When crossing water supply and sewer pipelines, the first ones are laid 0.4 m higher than the second ones (clear distance); with a smaller distance between them, water pipes should be laid in a metal sleeve with an extension of 0.5 m in both directions from the intersection point in dry soils, and 1 m in wet soils.
The diameter of the entry hole in the foundation wall or basement of a building must be 400 mm larger than the diameter of the entry pipe (Fig. 16). In dry soils, the annular gap between the input pipe and the steel sleeve is sealed with an elastic, water-gas-impermeable material, for example, crumpled clay, resinous strands and grade 300 cement mortar. , layer 20-30 mm; for wet soils - using a gland seal or concrete mortar grade 70 (hard seal).
In the second type of soil conditions at a construction site composed of macroporous subsidence soils, the inlet from steel pipes is laid in steel or cast iron sleeves, concrete or brick channels with waterproofing and a slope towards the external water supply.
The number of inputs is determined by the purpose and equipment of the buildings. So, in buildings (public, industrial), where a break in the water supply is unacceptable, at least two inlets are installed.
Internal water supply systems of clubs, theaters and buildings equipped with more than 12 fire hydrants are also connected to the external water supply network with at least two inlets.
Control questions
1. What is called entrance to the building?
2. What pipes are used for the installation of inputs?
3. When water lines intersect with sewer lines, how are they laid?
4. Methods for connecting inputs to an external water supply network.
1. Kedrov V.S. Sanitary equipment for buildings /
V.S. Kedrov. – M.: Higher. school, 1974.– 540 p.
2. Starinsky V.K. Water intake and treatment facilities
communal water pipelines / V.K. Starinsky, L.G. Mikhailik. – Minsk, 1989. – 362 p.
The inlet is the part of the pipeline that connects the external water supply to the water measuring unit in the house or at the central heating point. Knowledge of the rules for arranging the introductory area is necessary for the functional integration of elements of the water supply network located inside and outside the building.
Design and diagram of water supply network inputs
Pipeline entry through a brick wall
The inlet section connects the external water supply network from the connection point to the water measuring unit or shut-off element. The complex also includes sealing the passage of pipes into the house.
There are two types of introducing a water supply line into a building: from the central network or from a local water source. The decentralized method is used when water supply systems are located far from buildings. The connection is made from a well or well. Private houses are usually powered in this way; they have a single input.
In high-rise buildings, each water connection connects to 400 or fewer apartments. The number of inlet sections depends on the mode of providing moisture to consumers:
The total number of inputs is determined by the selected water supply scheme. In residential and public buildings of standard construction, there is usually one input node.
At the junction of the inlet and the external part of the water supply network, a well tank with a diameter of at least 70 cm is installed to accommodate shut-off valves. This can be a valve or gate valve that allows you to shut off the water flow at any time.
When installing two or more inputs, they are connected to different sections of the external ring main, installing a separating valve on it. If pressure equipment is additionally installed, which increases the pressure inside the water supply network, inlets are arranged in front of the pumps. At the same time, locking elements are mounted on the connecting element. They will provide moisture to all pumping equipment. The inputs are not connected if each of them is equipped with an independent pressure station.
If the house is connected to a centralized network, it is mandatory to install a water meter.
Connecting water inlets
The inlet section is connected to the external water supply network using one of the following methods:
- directly to the tees, crosses or plugged holes left during the construction of the city highway;
- connecting the pipe to the main line by welding or inserting a tee;
- by means of a saddle.
In the latter case, a cast-iron shaped part is used, securing it to the water supply with a clamp on a rubber gasket. The saddle is used when it is not possible to shut off the external water supply. A shut-off valve - a pass-through valve or gate valve - is fixed to it using a threaded or flanged connection. To drill a hole in the pipe, a drilling device is attached to the locking element.
A valve or gate valve is also installed at the point where an input with a cross-section of more than 50 mm is connected to an external water supply system. Input units are equipped with stops in areas of turns along a vertical or horizontal plane.
When installing several inlets with measuring instruments on an internal pipeline, connected by pipe sections, it is necessary to provide for the installation of check valves
Pipe materials and sizes
For the installation of inputs with a cross-section of 50 mm or more, cast iron pipes are predominantly chosen; for smaller diameters, pipelines made of steel, galvanized or polymers are chosen. Steel products without zinc coating with bitumen insulation against rust are used when the pressure in the line is more than 1 MPa and the cross-section of the inputs is more than 50 mm.
When selecting pipe sections according to cross-sectional size, they are based on two criteria: the speed of the water flow, as well as the total length of the water main. The first indicator is usually standard: water moves at a speed of approximately two meters per second. The second varies depending on the area of the building and the distance of plumbing fixtures. For example, with an expected water pipeline length of less than ten meters, pipe sections with a cross-section of 20 mm are sufficient, from 10 to 30 m - 25 mm and more than 30 m - 32 mm.
Building regulations
Installation diagram for water supply inlet into the house
The water supply entry point into the building is installed under a non-residential premises, for example, under a staircase, since there may be a station of two pumps nearby: a working one and a spare one. The location of pumping equipment under residential premises is prohibited by Building Codes and Rules 2.04.01-85.
The installation of the inlet pipeline is carried out at a minimum distance at an angle of 90 degrees to the wall of the house and with a slope of 0.005 to the city highway. This will allow excess moisture to drain out.
The introductory section at the point where it passes through the wall or foundation of the building must be protected from mechanical damage. To do this, pipe sections in dry soils are laid in cases made of steel sleeves with the annular gap sealed with tarred fiber and crushed clay, and on the outside with cement mortar for sealing. In soils saturated with moisture, ribbed pipes are used to arrange inputs passing through walls and foundations, and in the vicinity of subsurface sources, seals are used or sealed with cement or concrete mixture.
The size of the entry hole in the wall of the foundation or basement of the building must be 40 mm larger than the cross-section of the entry pipe.
The minimum distances in the horizontal direction from the input pipes to other underground communications are established by building regulations:
- to the heating main – 1.5 m;
- to the sewer main with an input cross-section of up to 20 cm - 1.5 m, more than 20 cm - 3 m;
- to low pressure gas networks – 1 m, medium – 1.5 m;
- to electrical cables and telephone wires – 0.75–1.0 m.
When crossing the sewer main, the water supply network is laid 40 cm higher. The inlet section is ideally also located above the sewer pipes. If the water supply inlet can be arranged only below the wastewater outlet, the distance criteria listed above must be increased by the difference in the depth of pipeline laying. In this case, it is imperative to use steel pipes placed in a case with an extension of up to a meter in both directions.
The depth of the water main entrance depends on how the external water supply pipeline runs. It is important that the introductory areas are located below the soil freezing level. The minimum depth for laying is a meter, but only if the ground temperature at this level is above zero. Be sure to take into account that to ensure free drainage from the system, the inlet is installed with a slope of 0.005 towards the external water supply network.
The arrangement of the introductory area should be provided for even before the construction of the building. If you encounter difficulties when creating a diagram of this unit yourself, you need to contact the design bureau.
Section 1
Internal water supply of buildings
The internal water supply includes:
1) pipelines and connecting fittings (fittings);
2) fittings (taps, mixers, valves, gate valves, etc.);
3) instruments (pressure gauges, water meters);
4) equipment (pumps).
Symbols for internal water supply see above.
Classification of internal water supply systems
The classification of internal water supply systems is shown in Fig. 1.
Thus, the internal water supply is divided primarily into cold (C) and hot (T) water supply. On diagrams and drawings in domestic documentation, cold water pipes are designated by the letter of the Russian alphabet B, and hot water pipes by the letter of the Russian alphabet T.
Cold water pipes have the following types:
B1 - domestic drinking water supply;
B2 - fire water supply;
B3 - industrial water supply (general designation).
A modern hot water supply must have two pipes in the building: T3 - supply, T4 - circulation. In passing, we note that T1-T2 designate heating systems (heating networks), which do not relate directly to the water supply system, but are connected to it, which we will consider later.
Water pipes
All indoor water pipes usually have the following internal diameters:
Æ 15 mm (in apartments), 20, 25, 32, 40, 50 mm. In domestic practice, steel, plastic and metal-polymer pipes are used.
Galvanized steel water and gas pipes in accordance with GOST 3262-75* are still widely used for drinking water supply B1 and hot water supply T3-T4. Since September 1, 1996, amendment No. 2 of SNiP 2.04.01-85 recommended for the listed water supply systems to primarily use plastic pipes made of polyethylene, polypropylene, polyvinyl chloride, polybutylene, metal-polymer, and fiberglass. It is allowed to use copper, bronze, brass pipes, as well as steel pipes with internal and external protective coating against corrosion.
The service life of cold water supply pipes must be at least 50 years, and hot water supply pipes must be at least 25 years. Any pipe must withstand an excess (gauge) pressure of at least 0.45 MPa (or 45 m of water column).
Steel pipes are laid openly with a gap of 3-5 cm from the building structure. Plastic and metal-polymer pipes should be laid hidden in baseboards, grooves, shafts and channels.
Methods for connecting water pipes:
1) Threaded connection. At the joints of pipes, shaped connecting parts (fittings) are used - see below. Threading on galvanized pipes is carried out after galvanizing. Pipe threads must be protected from corrosion by lubricant. The threaded connection method is reliable, but labor-intensive.
2) Welded connection. Less labor-intensive, but destroys the protective zinc coating, which must be restored.
3) Flange connection. It is mainly used when installing equipment (pumps, etc.).
4) Adhesive connection. Mainly used for plastic pipes.
Shaped parts (fittings)
Shaped parts (fittings) are mainly used for threaded connections of water pipes. They are made of cast iron, steel or bronze. Here are the most commonly used fittings:
Couplings (butt connection of pipes of equal or different diameters);
Angles (rotate the pipe 90°);
Tees (lateral pipe connections);
Crosses (lateral pipe connections).
Plumbing fittings
Plumbing fittings are used:
Water taps (water taps, bath taps, float valves for toilet flush tanks);
Mixing unit (faucets for sink, washbasin, common for bathtub and washbasin, with shower net, etc.);
Shut-off (valves for pipe diameters Æ 15-40 mm, valves for pipe diameters Æ 50 mm and more);
Safety (check valves are installed after the pumps).
For symbols of water fittings, see above.
Devices
Plumbing fixtures:
Pressure gauges (measure pressure and pressure);
Water meters (measure water flow).
For symbols of devices, see above.
Equipment
Pumps are the main equipment in the water supply system. They increase the pressure (pressure) inside the water pipes. The vast majority of water pumps are currently powered by electric motors. Pumps are most often used of the centrifugal type.
For pump symbols, see above.
Water quality requirements B1
Requirements for water quality in drinking water supply B1 can be divided into two groups:
Water must be potable, according to GOST 2874-82*;
The water should be cold, that is, with a temperature t » +8 ... +11 °C.
The drinking water standard contains three types of indicators:
1) PHYSICAL: turbidity, color, smell, taste;
2) CHEMICAL: total mineralization (no more than 1 g/liter - this is fresh water), as well as the content of inorganic and organic substances no more than maximum permissible concentrations (MAC);
3) BACTERIOLOGICAL: no more than three bacteria per liter of water.
The water temperature within t » +8 ... +11 °C is achieved due to the contact of the underground pipes of the external water supply with the ground, for which these pipes are not thermally insulated underground. External water supply is always laid at depths below the soil freezing zone, where temperatures are positive all year round.
Elements B1
We will consider the elements of the drinking water supply system B1 using the example of a two-story building with a basement (Fig. 2).
Elements of the drinking water supply system B1:
1 - water supply input;
2 - water metering unit;
3 - pumping unit (not always);
4 - water distribution network;
5 - water riser;
6 - floor-to-floor (apartment-by-apartment) water supply;
7 - water supply and mixing fittings.
Water supply inlet
The water supply inlet is a section of an underground pipeline with shut-off valves from the inspection well on the external network to the outer wall of the building where water is supplied (see Fig. 2).
Each water supply inlet in residential buildings is designed for a number of apartments of no more than 400. On diagrams and drawings, the inlet is designated, for example, as follows:
Input B1-1.
This means that the input relates to the drinking water supply system B1 and the serial number of the input is No. 1.
The depth of the water supply pipe is taken according to SNiP 2.04.02-84 for external networks and is found by the formula:
Hall = Npromerz + 0.5 m,
where Npromerz is the standard depth of soil freezing in a given area; 0.5 m - half a meter margin.
Water metering unit
A water metering unit (water metering frame) is a section of a water pipe immediately after the water supply system is entered, which has a water meter, a pressure gauge, shut-off valves and a bypass line (Fig. 3).
The water metering unit should be installed near the outer wall of the building in a convenient and easily accessible room with artificial or natural lighting and an air temperature of at least +5 °C in accordance with SNiP 2.04.01-85.
The bypass line of the water metering unit is usually closed, and the fittings on it are sealed. This is necessary to measure water through a water meter. The reliability of the water meter readings can be checked using a control valve installed after it (see Fig. 3).
Pumping unit
A pump installation on the internal water supply is necessary when there is a constant or periodic lack of pressure, usually when water does not reach the upper floors of the building through the pipes. The pump adds the necessary pressure in the water supply. The most commonly used pumps are centrifugal pumps driven by an electric motor. The minimum number of pumps is two, of which one is a working pump and the other is a reserve pump. The pumping installation diagram for this case is shown in axonometry in Fig. 4.
Water distribution network
Internal water supply distribution networks are laid, according to SNiP 2.04.01-85, in basements, technical undergrounds and floors, in attics, in the absence of attics - on the ground floor in underground channels together with heating pipelines or under the floor with a removable frieze device or under the ceiling top floor.
Pipelines can be attached:
With support on walls and partitions in the areas of mounting holes;
With support on the basement floor through concrete or brick pillars;
Supported by brackets along walls and partitions;
Supported by hangers to the ceilings.
In basements and technical undergrounds, pipes Æ 15, 20 or 25 mm are connected to the water distribution networks, supplying water to watering taps, which are usually led out into the niches of the basement walls at a height above the ground of about 30-35 cm. Along the perimeter of the building, watering taps are placed in increments 60-70 meters.
Water risers
A riser is any vertical pipeline. Water risers are placed and designed according to the following principles:
1) One riser for a group of nearby water distribution devices.
2) Mainly in bathrooms.
3) On one side of a group of nearby water taps.
4) The gap between the wall and the riser is 3-5 cm.
5) A shut-off valve is provided at the base of the riser.
Floor connections B1
Floor-to-floor (apartment-by-apartment) supply lines supply water from risers to water dispensing and mixing fittings: taps, mixers, float valves of flush tanks. The diameters of the connections are usually taken without calculation Æ 15 mm. This is due to the same diameter of the water supply and mixing fittings.
A shut-off valve Æ 15 mm and a VK-15 apartment water meter are installed on the supply line directly next to the riser. Next, the pipes are brought to the taps and mixers, and the pipes are laid at a height of 10-20 cm from the floor. In front of the flush tank, an additional valve is installed on the supply line to manually adjust the pressure in front of the float valve.
Rice. 5
Systems with fire hydrants are designed in accordance with SNiP 2.04.01-85, and semi-automatic (deluge) and automatic (sprinkler) installations are designed in accordance with SNiP 2.04.09-84.
HOT WATER PIPELINE T3-T4
A modern hot water supply T3-T4 has two pipes in the building: T3 ¾ is the supply pipeline; T4 ¾ circulation pipeline.
Water quality requirements T3-T4
Requirements for the quality of hot water in the T3-T4 system are contained in SNiP 2.04.01-85:
1) Hot water in T3-T4 must be potable in accordance with GOST 2874-82. The quality of water supplied for production needs is determined by technological requirements.
2) The temperature of hot water at water points should be provided:
a) not lower than +60°C ¾ for centralized hot water supply systems connected to open heat supply systems;
b) not lower than +50°C ¾ for centralized hot water supply systems connected to closed heat supply systems;
c) not higher than +75°С ¾ for all systems specified in subparagraphs “a” and “b”.
3) In the premises of preschool institutions, the temperature of hot water supplied for showers and washbasins should not exceed +37 °C.
Rice. 7
It should be noted that external hot water supply networks are usually not laid, that is, hot water supply T3-T4 ¾ is typically an internal water supply system. The classification shown in Fig. 7 reflects the fact that the location of the heat source is decided centrally or locally. In large and medium-sized cities, heat is carried by external water heating networks T1-T2 and heat is supplied to buildings by separate inputs T1-T2. These are centralized heating systems. In small towns and populated areas, the heat source is located in a house or apartment - this is a house boiler room or hot water column, running on gas, fuel oil, oil, coal, wood or electricity. This is a local system.
Open the hot water supply system (see Fig. 7) takes water from the return pipeline of the heating network T2 directly, directly, and then the water flows through pipe T3 to the mixers in the apartments. This hot water supply solution is not the best from the point of view of ensuring the potable quality of hot water, since the water actually comes from the water heating system. However, this solution is very inexpensive. In this way, for example, most buildings on the right bank of Omsk are supplied.
Closed The hot water supply system (see Fig. 7) takes water from the cold water supply B1. The water is heated using water heater-heat exchangers (boilers or high-speed) and flows through the T3 pipe to the mixers in the apartments. Some of the unused hot water circulates inside the building through the T4 pipeline, which maintains a constant required water temperature. The heat source for water heaters is the supply pipe of the heating network T1. This hot water supply solution is already better from the point of view of ensuring the drinking quality of hot water, since the water is taken from the drinking water supply system B1. In this way, for example, most buildings on the left bank of Omsk are supplied.
Elements T3-T4
Let's look at the elements of hot water supply T3-T4 using the example of Fig. 8.
1 ¾ input of the heating network into the technical underground of the building. This is not a hot water supply element.
2 ¾ thermal unit. Here the scheme is implemented ( open or closed) hot water supply.
3 ¾ water meter on the supply pipe of the hot water supply T3 at the heating unit.
4 ¾ distribution network of supply pipelines T3 hot water supply.
5 ¾ supply riser T3 hot water supply. A shut-off valve is installed at its base.
6 ¾ heated towel rails on T3 supply risers.
7 ¾ apartment hot water meters on floor-by-floor connections T3.
8 ¾ floor hot water connections T3 (usually Æ 15 mm).
9 ¾ mixing fittings (Fig. 8 shows a common mixer for a washbasin and a bathtub with a shower screen and a swivel spout).
10 ¾ circulation riser T4 hot water supply. A shut-off valve is also installed at its base.
11 ¾ outlet network of circulation pipelines T4 hot water supply.
12 ¾ water meter on the circulation pipe of the hot water supply T4 at the heating unit.
Section 2
DOMESTIC SEWERAGE K1
Domestic sewage system K1 is designed to drain wastewater from toilets, bathtubs, kitchens, showers, public restrooms, garbage disposals, etc. This is the main sewer system for buildings. Its old name is “domestic-fecal” sewerage.
K1 elements
Let's consider the elements of domestic sewage system K1 using the example of a two-story building with a basement (Fig. 13).
Here are the main elements of K1 along the flow of wastewater:
1 ¾ sanitary fixtures;
2 ¾ siphon (hydraulic seal);
3 ¾ floor outlet pipeline;
4 ¾ sewer riser;
5 ¾ drainage network in the basement;
6 ¾ sewer outlet.
Let's note some details. The knee is shown below the siphon. It is used on low risers (no more than 1 floor). The outlet pipeline 3 is laid with a slope and connected using a straight tee to the riser 4. Audits are installed on the riser.
The top of the riser is brought above the roof into the atmosphere to a height z¾ is the ventilation of the sewer riser. It is necessary to ventilate the inside of the sewer, as well as to prevent the appearance of excess pressure or, conversely, vacuum in the sewer. A vacuum can appear if the ventilation of the riser is faulty while draining water from the upper floor, which will lead to the siphon breaking down, that is, the water will leave the siphon on the lower floor and an odor will appear in the room.
The height of the riser above the roof is taken according to SNiP 2.04.01-85 to be no less than the following values:
z= 0.3 m¾ for flat unused roofs;
z= 0.5 m¾ for pitched roofs;
z= 3 m¾ for exploited roofs.
The sewer riser can be installed without ventilation, that is, not installed above the roof, if its height H st does not exceed 90 internal diameters of the riser pipe.
Recently, vacuum valves for sewer risers have appeared on sale, the installation of which at the level of the upper floor eliminates the need for a ventilation outlet for the riser above the roof of the building.
There are two outlets installed at the base of the riser, since the riser is the outermost one on the network in the basement. If the riser falls on the network pipe from above, then an oblique tee and a bend are used. It is impossible to use a straight tee in the basement, as the hydraulics of the drain deteriorate and blockages occur.
At the end of the outlet network 5 in front of the outer wall, a cleanout is assembled from a straight tee with a plug. Counting from this cleaning, the length of the sewer outlet L should not be more than 12 meters with a pipe diameter of Æ 100 mm, according to SNiP 2.04.01-85. On the other hand, the distance from the inspection well of the yard sewage system to the wall of the building should not be less than 3 meters. Therefore, the distance from the house to the well is usually 3-5 meters.
The depth of the sewer outlet from the ground surface to the tray (bottom of the pipe) at the outer wall is taken to be equal to the freezing depth in the given area, reduced by 0.3 meters (the influence of the building on the non-freezing of the soil next to the house is taken into account).
RAIN Drainage K2
Rainwater drainage system K2 is designed to drain atmospheric (rain and melt) water from the roofs of buildings through internal drains. Therefore, the second name is K2 ¾ internal drains.
There are three ways to remove atmospheric (rain and melt) water from the roofs of buildings:
1) Unorganized way. Suitable for one- and two-story buildings. Water simply drains from the eaves of the building, for which the offset of the eaves from the vertical surface of the outer wall must be at least 0.6 meters.
2) Organized method for external drains (this is not K2). Suitable for 3-5 storey buildings. A gutter is installed along the eaves of the building, which directs the flowing atmospheric water into drainage funnels. Next, the water flows down the external drainage risers and exits through the outlets onto the blind area of the building, which is usually reinforced with concreting to prevent erosion.
3) An organized method for internal drains ¾ is rainwater drainage K2). It is used for residential buildings with more than 5 floors, as well as for buildings of any number of storeys with a wide roof (more than 48 meters) or multi-span buildings (usually industrial buildings).
K2 elements
Let's consider elements of rainwater drainage system K2 using the example of a two-story building with a basement (Fig. 14).
1 ¾ drain funnel. Shown here is a bell-type funnel for unused roofs. Flat crowns are used for roofs in use. For symbols, see above. The brand of the funnel is selected according to its throughput, which is calculated according to the SNiP 2.04.01-85 method.
2 ¾ drain riser. It is laid in staircases and corridors.
3 ¾ revision.
4 ¾ siphon (hydraulic seal). It protects against the formation of an ice plug at the K2 outlet in the spring.
5 ¾ open release K2. Installed in the absence of an external drainage network K2. It is recommended to arrange it on the south side of the building. If there is an external drainage network K2, the discharge of rainwater drainage is arranged as in K1 (see above).
K3 elements
Let's look at the elements of industrial sewage system K3 using the example of a one-story industrial building, where mechanically contaminated industrial wastewater flows from the floor into a floor drain (funnel). Then the K3 system is specified by the K4 system.
K3 elements:
1 ¾ wastewater receiver (in this case, a drain).
2 ¾ drainage internal sewer network.
3 ¾ local treatment facility (sand trap, grease trap, oil trap, etc.).
4 ¾ pumping station.
5 ¾ release of sewer K3 into the city sewer network.
BUILDINGS WASTE CHECKPOINTS
Garbage chutes in buildings are installed to ensure the convenience of removing garbage through pipelines into containers located in garbage chambers, from where garbage is periodically removed. There is no special SNiP for garbage chutes. They are designed based on accumulated experience (standard projects). They are associated with the water supply and sewerage systems of buildings, especially in waste storage rooms.
Garbage chute elements
Let's look at the elements of garbage chutes using the example of a multi-storey residential building. These elements may be the following:
1 ¾ risers of the garbage chute are assembled from steel or concrete pipes with a diameter of 400-500 mm. On each floor or between floors, foot valves are installed on the riser.
2 ¾ above the roof the riser is brought to a height of about 1 meter and is equipped with a deflector to enhance the ventilation of the garbage chute.
3 ¾ downstairs there is a garbage room with a separate entrance. Here the riser has a flat gate valve
4 ¾ under the riser in the garbage chamber there is a container for collecting and removing garbage.
5 ¾ cold water B1 and hot water T3 are supplied to the waste disposal room to the mixer (watering tap), and a drain with a diameter of 100 mm is installed in the floor with a connection to the domestic sewerage system K1
6 ¾ under the ceiling of the garbage chamber, a sprinkler is installed (if the building has 10 or more floors) to automatically extinguish the fire with sprayed water.
Elements of utility networks 5 and 6 in the waste chamber are arranged in accordance with the requirements of SNiP 2.04.01-85.
Section 3
Elements of water supply schemes
Let's consider the elements of the external water supply scheme using the example of the city of Omsk (Fig. 16).
External water supply elements:
1 ¾ source of water supply;
2 ¾ water intake;
3 ¾ water lines;
4 ¾ water treatment station;
5 ¾ city water supply network with facilities.
Water supply sources
The source of water supply can be surface or underground. The share of surface sources (rivers, lakes, reservoirs, canals) is about 70%, and the share of underground (ground and pressure artesian waters) is ¾ about 30%. The source of water supply for Omsk is the Irtysh River.
Water intake structures
A water intake structure captures water from a water supply source, so water intakes can be respectively surface (shore, channel, bucket) or underground (wells, wells). Mixed are radial under-channel water intakes, which are made from horizontal wells, drilling them into under-channel alluvial deposits. Together with water intake they are usually combined pumping station I lift, which pumps untreated water to a water treatment plant.
Water pipelines
Water pipelines ¾ are pressure pipelines of significant cross-section. Their number must be at least two (in two threads). Water is pumped through water pipelines to the city water treatment plant.
Water treatment plants: processes and structures
A water treatment station ¾ is an entire industrial site for the preparation of drinking water for a city or town. At the water treatment plant facilities, processes are carried out to prepare drinking water, which is shown in comparison in the table below.
| Processes | Facilities |
| Water settling. The water contains grains of sand and silt particles. Therefore, they must be extracted by settling. The water should not stand, but flow slowly, at a speed of approximately 1 cm/s, that is, in laminar mode. Contaminants precipitate and primary water purification occurs. | Septic tanks. These are flow-through structures where water moves slowly, at a speed of approximately 1 cm/s, that is, in laminar mode. Therefore, contaminants precipitate and primary water purification occurs. Septic tanks are built from reinforced concrete. |
| Water filtering. It is produced for the final purification of water from mechanical contaminants that cannot be removed by settling. To effectively and quickly purify water by filtering through a porous media (sand, expanded clay), the water is first treated with chemical reagents to form flakes from suspensions in the water. | Fast filters. First, the water is treated with chemical reagents, for example aluminum sulfate Al2(SO4)3. Then the fine suspensions in the water coagulate into flakes and are then effectively deposited on the filter media. This is the technology for operating fast filters with large loads, for example, made from expanded clay chips. |
| Water disinfection. Water contains bacteria, including pathogenic ones. Water disinfection is most often done by chlorination. There are also known methods for water ozonation and ultraviolet treatment. | Water disinfection facilities. When chlorinating water, chlorination facilities are used, when ozonating, ozonizers (electric dischargers) are used, and ultraviolet lamps are used for clear waters, usually underground. |
External water supply networks
And the buildings on them
The water supply network is laid throughout the city with a ring of highways around the main districts, microdistricts and industrial sites (see Fig. 16). The laying depth of water supply pipes is taken equal to the standard freezing depth in the given area plus a margin of 0.5 meters. Pipes with a small diameter of 100-200 mm are mounted from steel with an anti-corrosion coating or from cast iron. Larger diameter pipes are laid from reinforced concrete. Recently, plastic pipes have been used.
Facilities on the city water supply:
¾ inspection wells with valves and fire hydrants (near buildings), well spacing 100-150 meters;
¾ pumping stations (district and local) to compensate for pressure losses in the water supply system, and the guaranteed pressure must be maintained within 10< H < 60 м водяного столба.
Section 4
END OF LECTURE COURSE
APPLICATION
Checklist
1. Which system is designated as B1?
2. What is K1?
3. What is internal water supply according to SNiP 2.04.01-85?
4. What is K2?
5. What is B2?
6. What is internal sewerage according to SNiP 2.04.01-85?
7. What is B3?
8. What is K3?
9. What is T3-T4?
10. What is the maximum distance between drains on the roofs of buildings?
11. What is the most representative list of requirements for water quality in B1?
12. What is the list of elements of the internal system K1?
13. List the elements of internal B1 (in the direction of water movement)?
14. What are the most commonly used pipe diameters in internal K1?
15. Standard water flow from the tap in B1?
16. Where are oblique tees used in K1, taking into account the requirements of SNiP 2.04.01-85?
17. Types of pressure losses in the water supply network?
18. Where are straight crosses used in the K1 internal system?
19. Select the interval of economical speeds when calculating internal B1?
20. Where, according to SNiP 2.04.01-85, should revisions be installed?
21. What is the diameter range of steel pipelines for internal B1?
22. How are sewer pipes connected?
23. Permissible pressure losses at water meters according to the requirements of SNiP 2.04.01-85?
24. What is a kabolka (emphasis on the first syllable)?
25. Caliber range of vane (VK) and turbine (VT) water meters?
26. What are siphons in K1?
27. Maximum pressure in internal B1 according to SNiP 2.04.01-85?
28. What devices are installed to clean the internal K1?
29. Methods for laying water pipes in buildings according to SNiP 2.04.01-85?
30. Indicate the calculated fillings in pipes K1?
31. Methods of fastening water pipes?
32. Permissible speed range for wastewater in the sewer (m/s)?
33. Minimum free pressures in front of mixers for sinks and showers according to SNiP 2.04.01-85?
34. Why are siphons (water seals) installed in K2 systems?
35. Methods for connecting internal water supply pipes?
36. What is the range of slopes of sewer pipes?
37. Diameters of fire hydrants for internal B2?
38. What is the K4 system?
39. What are deluge and sprinkler systems?
40. What methods are used to test internal sewage systems K1 and K2?
41. Standard value of water flow from a fire hydrant
42. At what percentage of physical wear does the internal water supply system require major repairs?
43. What are B4 and B5?
44. Requirements for water quality in T3 according to SNiP 2.04.01-85?
45. What are open and closed T3 systems in buildings?
46. When are internal water pipes installed in a building?
47. Estimated service life of internal T3 according to SNiP 2.04.01-85 (in years)?
48. Estimated period of operation of internal water supply systems B1 according to SNiP 2.04.01-85 (in years)?
49. Precise definition of building drainage?
50. What is hydraulic slope?
51. What is included in the internal water supply?
52. Methods for installing internal sewerage?
53. Priority for using water pipe material according to SNiP 2.04.01-85 (as amended in 1996)?
54. List the set of sanitary and technical equipment. devices for apartment-type residential buildings?
55. Classification of industrial water supply according to water use?
56. What is included in the internal sewage system?
57. Minimum depth of water supply inlet from the ground surface?
58. Minimum depth of sewer outlet?
59. What are fittings?
60. List the characteristic elements of the K3 internal system?
61. How to decipher the designations of pipes T3-T4?
62. List the characteristic elements of the K2 internal system?
64. What are floor drains?
65. What is the difference between systems T1...T2 and T3...T4?
66. Does the K2 system include such methods for removing atmospheric water from the roofs of buildings?
67. According to SNiP 2.04.01-85, is the B2 system used in the following residential buildings?
68. Knee and abduction - how do they differ in the K1 system?
69. Pressures in the internal water supply system B1 are controlled using what?
70. The height of the riser K1 above the roof according to SNiP 2.04.01-85 should be no less?
71. Where should purgings be installed on internal K1 systems?
72. What is guaranteed pressure?
73. How are the sockets of cast iron and plastic sewer pipes sealed?
74. Bypass line at the water metering unit of system B1?
75. Where is FUM tape used in building engineering networks?
76. Bypass line in the pumping unit of system B1?
77. Water consumption rate B1 per inhabitant in an apartment with bathtubs from 1500 to 1700 mm long?
78. Maximum height of an unventilated riser K1?
79. What devices are used in the internal system B1?
80. What is the minimum slope that can be accepted for sewer pipes K1?
81. What is EQUIPMENT in the internal system B1?
82. What is REVISION in the K1 internal system?
83. At what spacing are watering taps placed around the perimeter of the building?
84. What causes the breakdown of siphons (hydraulic seals) in K1 systems?
85. Who should punch mounting holes for passing pipes in the walls and floors of apartments?
86. Types of drainage funnels of the K2 internal system?
87. The fire hydrant for internal B2 is placed above the floor at what height?
88. What structures may be included in the K3 internal system?
89. What are sprinkler and deluge in fire extinguishing systems?
90. What is checked when testing and commissioning the internal system K1
91. How to turn on the sprinkler installation?
92. Which document regulates testing of internal water supply?
93. Should the water temperature in pipes T3-T4 be appropriate?
94. In preschool institutions, should the water temperature in T3 pipes be?
95. Which pipe should be used for a heated towel rail?
96. Who in the building installs mounting embedded parts for fastening elements B2?
97. What is a boiler?
98. The main type of pumps for internal water supply systems is B1?
99. What is the vacuum valve on the sewer riser K1 for?
100. A sprinkler under the ceiling of a garbage chamber is installed at what number of floors in a building?
101. In garbage chambers of residential buildings, what should be installed from the water supply?
102. In garbage chambers of residential buildings, what should be installed on the sewer system?
103. Water meters should be installed in rooms with what air temperature?
104. What is a water intake?
105. What is a digester?
106. Average speed of water movement in the sump?
107. For a sewer pipe d=150 mm, is the maximum distance between wells?
108. For a sewer pipe d=200 mm, is the maximum distance between wells?
109. SHELYGA IN SHELYGA – what is it?
110. TRAY near the sewer pipe - what is it?
111. The main structures included in biological treatment?
112. Length of the sewer outlet from the outer wall to the manhole?
113. Where in apartments should shut-off valves be installed according to SNiP 2.04.01-85?
114. Optimal slopes for K1 pipes with a diameter of 50 and 100 mm?
115. List the city sewer networks sequentially according to the direction of wastewater flow?
116. The pressure in the T3 system near water taps should be no more than:
117. The hydrostatic head in the B2 system of buildings should not exceed (in meters)?
118. The hydrostatic head in the B1+B2 system of buildings should not exceed (in meters)?
119. Standard lengths of fire hoses for B2 according to SNiP 2.04.01-85?
120. How to determine the number of water supply connections for a residential building?
121. Minimum horizontal clear distance between input B1 and outlet K1?
122. Where should the B1 distribution network be laid first in residential buildings?
123. Where should drinking fountains be located in industrial buildings?
124. Material of internal T3 shut-off valves with a diameter of up to 50 mm inclusive?
125. What is an aeration tank?
Section 1
Internal water supply of buildings
The internal water supply of buildings is a system of pipelines and devices that supply water inside buildings, including the water supply input that is located outside.
Internal water supply
The general plan outlines the entry of water supply into the building. The number of inputs is determined by the selected system and plumbing scheme. Residential and public buildings usually have one input. Two or more inputs should be provided (SNiP 2.04.01-85 ⋆) for residential buildings with more than 400 apartments or residential buildings with more than 12 floors.
The inlet is an underground pipeline that supplies water from the external network to the building. The inlet is designed either in the center of the building, shortening the path of water movement to the most distant water collection point with a symmetrical building layout, or at the end of the building, if the city water supply runs along the end of the building. It starts from a well with a valve and a fire hydrant - a connection point to the external water supply network. Water supply inlets are made of cast iron or polymer (HDPE, PVC) pipes. Steel pipes are not used at inputs in St. Petersburg due to their high corrosivity. In relation to the outer wall of the building, the inputs are made perpendicular. Directly through the outer wall of the building, as well as when crossing the main walls inside the building, pipelines are laid in sleeves. The size of the holes, sleeves and methods of sealing them depend on the diameter of the input and the groundwater level.
The depth of the input pipelines depends on the depth of the external water supply networks and must exceed the freezing depth of the soil by at least 0.5 m. The inputs are laid straight vertically with a slope of 0.005 towards the external network for possible emptying and removal of air through sanitary fixtures when minimal water consumption. At the point where the input is connected to the external network (Fig. 3), at a distance no further than 6 m from the insertion point, a shut-off valve is installed. When placing the valve on the roadway, it is advisable to install well-free shut-off valves; on lawns, installation of valves in wells is allowed.
It is better to arrange the inlet under a non-residential premises, for example, under a staircase, since next to the inlet there may be a pumping installation of at least two pumps: a working one and a backup one. But pumps cannot be located under residential premises, according to SNiP 2.04.01-85.
Initially, the entry diameter is unknown, although the general plan shows 32 mm. The diameter is found using hydraulic calculation, which is discussed below.
2.3. Water metering unit.
The water metering unit is installed immediately (no further than 1.5-2.0 m) behind the outer wall of the building in a lit, accessible, heated (temperature not lower than 5 °C) room.
Water meter units are usually installed in the basement of a building. If there is no basement, the water metering unit can be installed in a special pit (most often on a staircase) or in a specially designated room on the first floor, which has a separate entrance. The water metering unit is equipped with a water meter, a coarse filter (to remove mechanical impurities), valves for possible repair or replacement of the meter, straight pipes both before and after the meter (the length of the straight pipeline before the meter is at least five pipe diameters, after the meter - at least two). If there is insufficient space for installing a conventional water metering unit, it is recommended to use flow straighteners, including a valve with a filter, designed by TsIRV (Center for Water Flow Measurement of the State Unitary Enterprise "Vodokanal" St. Petersburg). If there is one entrance to the building, the water metering unit must be equipped with a bypass line. A bypass line is also installed when fire-fighting flow is passed through. In this case, it must be equipped with a water meter. TsIRV also developed standard units of water metering units used in the design of water metering units.
